In a speech to prison reformers, Mr Clarke will admit that prisons are experiencing huge difficulties because of rising numbers of inmates and say that alternatives to custody must be used more widely.

This comes as prison officials face serious problems with overcrowding as a result of the prison population topping its maximum capacity in recent weeks of 77,000 jail places.

This has meant that the prison service has been forced to convert jails previously used for women into male establishments. Emergency plans have also been put in place to use police cells if the population rises much further.

Prison reformers say too many offenders, especially young people, are being sent to jail for trivial offences such as shoplifting and drug abuse because of government pressure on courts to get tough on anti-social behaviour.

The Government's youth justice chief has already warned of an increased risk of suicide and self-harm in youth jails because of a huge rise in numbers over the summer.

A Home Office source said that Mr Clarke will use a speech to the Prison Reform Trust in London to argue that community punishments are not a soft option and that they must be used more widely for low-level offenders. He will also stress that new ways must be found to stop people offending in the first place.

The source said: "He is going to acknowledge that there are pressures on the system which are creating difficulties and that we now have community sentences which are much tougher and could be used more widely, but he also wants to ensure that less people get involved in offending."